The present invention relates to an optical disk apparatus which performs recording or reproduction of information into/from an optical disk and, more particularly, to one which can perform adjustment of a track error signal reliably and effectively thereby to shorten a start-up time at starting this apparatus into which an optical disk medium is installed.
Hereinafter, a conventional optical disk apparatus will be described.
FIG. 14 is a block diagram illustrating a constitution of the conventional optical disk apparatus.
In FIG. 14, numeral 2 denotes an optical disk medium such as a CD, a CD-ROM, a DVD, and an MO, which has a track for information recording, and numeral 1 denotes an optical pickup which collects a semiconductor laser to irradiate the light to a target position on the optical disk medium 2, thereby to perform recording and reproduction of information, and this comprises an optical system and a driving system. The optical system collects a laser beam on the surface of the optical disk medium 2 or detects a deviation between a irradiated position of a laser beam and a target position on the optical disk medium 2, and it comprises a semiconductor laser, lenses, a beam splitter, a photodiode or the like (all not shown). On the other hand, the driving system is driven to perform a focus control which makes an objective lens follow plane wobbles on the optical disk medium 2 or a tracking control which makes the objective lens follow track wobbles, and keeps the positional relationship between the target position on the optical disk medium 2 and a laser beam spot constant, and it mainly comprises a magnet, a coil, and a support member (all not shown). The driving system serves as an actuator which drives the lenses of the optical system.
Numeral 3 denotes an operational amplifier which performs various arithmetic processings to a returned light quantity signal from the optical disk medium 2 which returned light is detected by photodiodes which are divided into plural parts, which photodiodes construct the optical pickup 1, and it outputs a focus error signal (hereinafter, referred to as FE signal) presenting a focus deviation quantity of the laser beam spot on the optical disk medium 2, a track error signal (hereinafter, referred to as TE signal) presenting a positional deviation amount of the laser beam spot with relative to a track on the optical disk medium 2, and a reproduction signal (hereinafter, referred to as RF signal) presenting information recorded as a change in light reflectance on the optical disk medium 2. Numeral 4 denotes a focus control circuit which performs a focus control of collecting the laser beam irradiated from the optical pickup 1 to focus the same on the optical disk medium 2, numeral 5 denotes a focus driving circuit which is controlled by the focus control circuit 4 and drives an actuator of an objective lens of the optical pickup 1, and numeral 6 denotes a micro processing unit (hereinafter, referred to as MPU) presenting an arithmetic processing unit, and by a command of this MPU 6, ON/OFF of the above-mentioned focus control operation is operated. Numeral 7 denotes an adjusting circuit which comprises an offset control circuit 71 and a variable gain amplifier 72, and receives the TE signal outputted from the operational amplifier 3, adjusts a gain and an offset by settings from the MPU 6, and outputs a track error signal after adjustment (hereinafter, referred to as a TEA signal), numeral 8 denotes a tracking control circuit which receives the TEA signal and performs a control so that the irradiated position of the laser beam follows the track of the optical disk medium 2, and numeral 9 denotes a tracking driving circuit which drives the objective lens of the optical pickup 1 with controlled by the tracking control circuit 8, and ON/OFF of this tracking control operation is operated by a command of the MPU 6.
Numeral 10 denotes a traverse control circuit which receives a control output signal (hereinafter, referred to as TRO signal) outputted from the tracking control circuit 8, and generates a TVO signal presenting a control signal for moving the optical pickup 1 itself to follow in a radial direction of the optical disk 2 when the irradiated position of the laser beam of the optical pickup 1 follows the spiral track on the optical disk medium 2, numeral 11 denotes a traverse driving circuit which receives the TVO signal and drives an after-mentioned traverse motor 12, and numeral 12 denotes a traverse motor which moves the optical pickup 1 in a radial direction of the optical disk medium 2. Further, numeral 13 denotes a signal processing circuit which receives the RF signal outputted from the operational amplifier 3, and reproduces information from the optical disk medium 2, and it extracts a SYNC signal presenting a synchronization signal from the RF signal. Numeral 14 denotes a spindle motor control circuit which receives the SYNC signal extracted from the signal processing circuit 13 and outputs a DMO signal for controlling the rotation number of the optical disk medium 2, numeral 15 denotes a spindle motor driving circuit which receives the DMO signal from the spindle motor control circuit 14 and drives an after-mentioned spindle motor, and numeral 16 denotes a spindle motor for rotating the optical disk medium 2, and the rotation of the spindle motor 16 can be also controlled at a prescribed rotation number by inputting an FG signal indicating a rotation number to the spindle motor control circuit 14, not by the SYNC signal.
Next, an adjusting operation of the track error signal, which is performed when the conventional optical disk apparatus on which the optical disk medium 2 is mounted is started will be described with reference to the flow chart in FIG. 15.
When the optical disk medium 2 is mounted on the optical disk apparatus or the power is turned ON (Step S901), the MPU 6 initializes the position of the optical pickup 1 (Step S902). More specifically, the traverse motor 12 is driven so as to move the optical pickup 1 forcibly to the inner periphery side of the optical disk medium 2 until an innermost periphery switch (not shown) is pressed (Step S903). When there is no innermost periphery switch, the traverse motor 12 is kept driven while the optical pickup 1 is surely moved to a limit of the movable range in which the optical pickup 1 can move to the inner periphery side. After the optical pickup 1 is moved to the innermost periphery position of the optical disk medium 2 in this way, the optical pickup 1 is moved to the outer periphery side for a prescribed time so as to be located at a position where the track on the optical disk medium 2 exists (Step S904).
FIG. 16 illustrates an area structure of the optical disk medium, such as a general compact disk (hereinafter, referred to as a CD), a recordable CD-R, or a rewritable CD-RW, in a radial direction. As shown in FIG. 16, the innermost periphery part is a clamp area A1 for mounting the disk, and an information area A2 where a track exists exists outside the clamp area. In the inner periphery and outer periphery of the information area A2, there exist mirror surface areas A30 and A31 in which a reflecting layer is formed but no tracks exist and substrate areas A40 and A41 made only of transparent substrates. Therefore, the optical pickup 1 is located in the information area A2 of the optical disk medium 2 by the above-described operation of initializing the position of the optical pickup 1.
Next, a returned light quantity from the optical disk medium 2 when an objective lens of the optical pickup 1 is operated up and down in a focus direction is detected from the level of the RF signal, and the presence or absence of the disk is judged (Step S905). At that time, it is utilized that a prescribed RF signal level can be obtained when the optical disk medium 2 is actually mounted on the optical disk apparatus. As the result of the judgement, when the optical disk medium 2 is judged to be mounted, the spindle motor 16 is driven to rotate the optical disk medium 2 (Step S906), and the focus control of the optical pickup 1 is turned ON (Step S907).
The collected laser beam spot crosses the track on the optical disk medium 2 due to eccentricity of the optical disk medium 2 itself or the deviation of the center at mounting or the like. This state is referred to as track cross state. While the TE signal at the track cross state is of an almost sine wave form as shown in FIG. 17, its signal amplitude or signal offset may be changed due to difference in reflectance of the optical disk medium 2, difference in sensitivity of the photodiode, asymmetry of groove shape in the track, or the like. Then, the TE signal has its gain and offset adjusted by the offset adjusting circuit 71 and the variable gain amplifier 72 that construct the adjusting circuit 7 based on setting from the MPU 6, so that the TEA signal presenting a track error signal after adjustment as shown in FIG. 17 is generated (Step S908). The track error signal is subjected to adjustment in this way, whereby a control operation can be performed so that the laser beam spot of the optical pickup 1 performs tracking accurately in the center of the track on the optical disk medium 2.
When the tracking control is prepared to be operated accurately by the above-described adjustment of the track error signal, the tracking control is turned ON (Step S909), and a traverse following control is subsequently turned ON so that the laser beam spot of the optical pickup 1 follows the spiral track on the optical disk medium 2 (Step S910).
In this way, the laser beam spot of the optical pickup 1 can accurately follow the track on the optical disk medium 2, whereby information in the optical disk medium 2 can be reproduced (Step S911), and the start-up of the optical disk apparatus is completed.
The so-constructed conventional optical disk apparatus transfers the optical pickup in a radial direction of the optical disk medium at a prescribed speed with the position of the objective lens of the optical pickup held, and almost prescribed track cross frequency is obtained, thereby to enhance adjustment accuracy of the amplitude and offset of the track error signal.
However, the above-described conventional optical disk apparatus have the following problem.
That is, the conventional optical disk apparatus is required to initialize the position of the optical pickup 1 before adjusting the track error signal, and to move the optical pickup 1 to the initialized position in several seconds so as to move the optical pickup 1 with no impulse added or no noise generated when moving the same to the innermost periphery position.
Therefore, the optical pickup 1 needs to be subjected to the moving operation to the initialized position though its position at start-up is within the information area where the track on the optical disk medium 2 exists, excepting such a specific situation where an abnormal operation termination is generated as a case where the optical pickup 1 is in runaway state and the power is turned OFF, whereby a start-up time of the optical disk apparatus until information from the optical disk medium 2 is read to be recorded/reproduced becomes longer.
The present invention is made to solve the above-mentioned problem and has for its object to obtain an optical disk apparatus which performs adjustment of a track error signal accurately and effectively, thereby to shorten a start-up time.
To solve the above-described problem, an optical disk apparatus according to claim 1 of the present invention comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: an amplitude detecting means for detecting amplitude of the track error signal; and a transfer means for transferring the optical pickup in a radial direction of the optical disk medium, and the focus control means focuses the light beam irradiated from the optical pickup onto the optical disk medium, and the adjusting means adjusts the gain and offset of the track error signal when the amplitude of the track error signal detected by the amplitude detecting means is equal to or larger than a previously set value, while the optical pickup is transferred to a previously decided position when the amplitude of the track error signal detected by the amplitude detecting means is under the previously set value.
According to the present invention, shift of the optical pickup to the initialized position at start-up can be almost eliminated, resulting in drastic reduction of a startup time.
According to claim 2 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: an amplitude detecting means for detecting amplitude of the track error signal; an objective lens shift means for providing a signal to the tracking driving means to shift an objective lens of the optical pickup in a radial direction of the optical disk medium; and a transfer means for transferring the optical pickup in the radial direction of the optical disk medium, and the focus control means focuses the light beam irradiated from the optical pickup onto the optical disk medium, and according to a first comparison result which is obtained by comparing amplitude of a first track error signal detected in the amplitude detecting means with a previously set value in a state where the objective lens of the optical pickup is shifted in an outer periphery direction of the optical disk medium by the objective lens shift means, as well as a second comparison result which is obtained by comparing amplitude of a second track error signal detected in the amplitude detecting means with the previously set value in a state where the objective lens of the optical pickup is shifted in an inner periphery direction of the optical disk medium by the objective lens shift means, the gain and offset of the track error signal are adjusted when the first and the second comparison results are both equal to or larger than the previously set value; the optical pickup is transferred in the outer periphery direction of the optical disk medium when the first comparison result is equal to or larger than the previously set value and the second comparison result is under the previously set value; the optical pickup is transferred in the inner periphery direction of the optical disk medium when the first comparison result is under the previously set value and the second comparison result is equal to or larger than the previously set value; and the optical pickup is transferred to a previously decided position when the first and the second comparison results are both under the previously set value.
According to the present invention, it is decided whether the optical pickup needs to be moved before the adjusting operation of the track error signal is performed, and the optical pickup can be moved to the most appropriate direction also when the movement is judged to be required, whereby the movement of the optical pickup can be optimized even when the optical pickup is located at a boundary of the area where the track on the optical disk medium exists at startup, resulting in drastic reduction of a startup time.
According to claim 3 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: an amplitude detecting means for detecting amplitude of the track error signal; an objective lens shift means for providing a signal to the tracking driving means to shift an objective lens of the optical pickup in a radial direction of the optical disk medium; and a transfer means for transferring the optical pickup in the radial direction of the optical disk medium, and the transfer means transfers the optical pickup in an outer periphery direction of the optical disk medium, the focus control means focuses the light beam irradiated from the optical pickup onto the optical disk medium, and shift of the objective lens is stopped and the adjusting means adjusts the gain and offset of the track error signal when the amplitude of the track error signal detected by the amplitude detecting means is equal to or larger than a previously set value in a state where the objective lens of the optical pickup is shifted in the outer periphery direction of the optical disk medium by the objective lens shift means, while the optical pickup is transferred in an inner periphery direction of the optical disk medium when the amplitude of the track error signal detected by the amplitude detecting means is under the previously set value.
According to the present invention, the amount of the optical pickup moving at startup can be drastically decreased, resulting in drastic reduction of a startup time.
According to claim 4 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: an amplitude detecting means for detecting amplitude of the track error signal; an objective lens shift means for providing a signal to the tracking driving means to shift an objective lens of the optical pickup in a radial direction of the optical disk medium; and a transfer means for transferring the optical pickup in the radial direction of the optical disk medium, and the transfer means transfers the optical pickup in an inner periphery direction of the optical disk medium, the focus control means focuses the light beam irradiated from the optical pickup onto the optical disk medium, and shift of the objective lens is stopped and the gain and offset of the track error signal are adjusted by the adjusting means when the amplitude of the track error signal detected by the amplitude detecting means is equal to or larger than a previously set value in a state where the objective lens shift means shifts the objective lens of the optical pickup in the inner periphery direction of the optical disk medium, while the optical pickup is transferred in an inner periphery direction of the optical disk medium when the amplitude of the track error signal detected by the amplitude detecting means is under the previously set value.
According to the present invention, the amount of the optical pickup moving at startup can be drastically decreased, resulting in drastic reduction of a startup time.
According to claim 5 of the present invention, in the optical disk apparatus as defined in any of claims 1 to 4, the amplitude of the track error signal is detected by the amplitude detecting means for a period of one rotation or more in synchronization with the rotation of the optical disk medium.
According to the present invention, amplitude of the track error signal can be certainly detected even when the status of the track error signal is changed due to eccentricity of the optical disk medium itself, the deviation of the center at mounting, vibration of the objective lens of the optical pickup, or the like.
According to claim 6 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: a returned light quantity detecting means for detecting a returned light quantity from the optical disk medium; an amplitude detecting means for detecting amplitude of an output signal of the returned light quantity detecting means; and a transfer means for transferring the optical pickup in a radial direction of the optical disk medium, and the focus control means focuses the light beam from the optical pickup onto the optical disk medium, and the adjusting means adjusts the gain and offset of the track error signal when the amplitude of the returned light quantity signal detected by the amplitude detecting means is equal to or larger than a previously set value, while the optical pickup is transferred to a previously decided position when the amplitude of the returned light quantity signal detected by the amplitude detecting means is under the previously set value.
According to the present invention, shift of the optical pickup to the initialized position at start-up can be almost eliminated, resulting in drastic reduction of a startup time.
According to claim 7 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: a returned light quantity detecting means for detecting a returned light quantity from the optical disk medium; an amplitude detecting means for detecting amplitude of an output signal of the returned light quantity detecting means; an objective lens shift means for providing a signal to the tracking driving means to shift an objective lens of the optical pickup in a radial direction of the optical disk medium; and a transfer means for transferring the optical pickup in the radial direction of the optical disk medium, and the focus control means focuses the light beam irradiated from the optical pickup onto the optical disk medium, and according to a first comparison result which is obtained by comparing amplitude of a first returned light quantity signal detected in the amplitude detecting means with a previously set value in a state where the objective lens of the optical pickup is shifted in an outer periphery direction of the optical disk medium by the objective lens shift means, as well as a second comparison result which is obtained by comparing amplitude of a second returned light quantity signal detected in the amplitude detecting means with the previously set value in a state where the objective lens of the optical pickup is shifted in an inner periphery direction of the optical disk medium by the objective lens shift means, the gain and offset of the track error signal are adjusted when the first and the second comparison results are both equal to or larger than the previously set value; the optical pickup is transferred in the outer periphery direction of the optical disk medium when the first comparison result is equal to or larger than the previously set value and the second comparison result is under the previously set value; the optical pickup is transferred in the inner periphery direction of the optical disk medium when the first comparison result is under the previously set value and the second comparison result is equal to or larger than the previously set value; and the optical pickup is transferred to a previously decided position when the first and the second comparison results are both under the previously set value.
According to the present invention, it is decided whether the optical pickup needs to be moved before the adjusting operation of the track error signal is performed, and the optical pickup can be moved to the most appropriate direction also when the movement is judged to be required, whereby the movement of the optical pickup can be optimized even when the optical pickup is located at a boundary of the area where the track on the optical disk medium exists at startup, resulting in drastic reduction of a startup time.
According to claim 8 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: a returned light quantity detecting means for detecting a returned light quantity from the optical disk medium; an amplitude detecting means for detecting amplitude of an output signal of the returned light quantity detecting means; an objective lens shift means for providing a signal to the tracking driving means to shift an objective lens of the optical pickup in a radial direction of the optical disk medium; and a transfer means for transferring the optical pickup in the radial direction of the optical disk medium, and the transfer means transfers the optical pickup in an outer periphery direction of the optical disk medium, the focus control means focuses the light beam from the optical pickup onto the optical disk medium, and shift of the objective lens is stopped and the gain and offset of the track error signal are adjusted by the adjusting means when the amplitude of the returned light quantity signal detected by the amplitude detecting means is equal to or larger than a previously set value in a state where the objective lens of the optical pickup is shifted in the outer periphery direction of the optical disk medium by the objective lens shift means, while the optical pickup is transferred in an inner periphery direction of the optical disk medium when the amplitude of the returned light quantity signal detected by the amplitude detecting means is under the previously set value.
According to the present invention, the amount of the optical pickup moving at startup can be drastically decreased, resulting in drastic reduction of a startup time.
According to claim 9 of the present invention, an optical disk apparatus comprising: an optical pickup which performs recording or reproduction of information into/from an optical disk medium having a track for information recording; a focus control means for controlling the optical pickup so as to focus a light beam on the optical disk medium; a tracking actuator which drives the optical pickup so that an irradiated position of the light beam follows the track for information recording; a track error detecting means for detecting a deviation from the track position of the irradiated position of the light beam; an adjusting means for adjusting gain and offset of a track error signal outputted by the track error detecting means; and a tracking driving means for driving the tracking actuator according to an output signal of the adjusting means, comprises: a returned light quantity detecting means for detecting a returned light quantity from the optical disk medium; an amplitude detecting means for detecting amplitude of an output signal of the returned light quantity detecting means; an objective lens shift means for providing a signal to the tracking driving means to shift an objective lens of the optical pickup in a radial direction of the optical disk medium; and a transfer means for transferring the optical pickup in the radial direction of the optical disk medium, and the transfer means transfers the optical pickup in an inner periphery direction of the optical disk medium, the light beam irradiated from the optical pickup is focused onto the optical disk medium by the focus control means, and shift of the objective lens is stopped and the gain and offset of the track error signal are adjusted by the adjusting means when the amplitude of the returned light quantity signal detected by the amplitude detecting means is equal to or larger than a previously set value in a state where the objective lens of the optical pickup is shifted in the inner periphery direction of the optical disk medium by the objective lens shift means, while the optical pickup is transferred in an outer periphery direction of the optical disk medium when the amplitude of the returned light quantity signal detected by the amplitude detecting means is under the previously set value.
According to the present invention, the amount of the optical pickup moving at startup can be drastically decreased, resulting in drastic reduction of a startup time.
According to claim 10 of the present invention, in the optical disk apparatus as defined in any of claims 6 to 9, the amplitude of the returned light quantity signal is detected by the amplitude detecting means for a period of one rotation or more in synchronization with the rotation of the optical disc medium.
According to the present invention, amplitude of the track error signal can be certainly detected even when the status of the returned light quantity signal is changed due to eccentricity of the optical disk medium itself, the deviation of the center at mounting, vibration of the objective lens of the optical pickup, or the like.